Heat exchanger



' Jan. 3, 1928.

R. L. BLANESING HEAT EXCHANGER 2 Sheets-Sheet 1 Filed March zzw INVENTOR Jan. 3, 1928.

' R. L. BiLANDING HEAT EXC HANGER Fild March 26. 19

26 2 Sheets-Sheet 2 Patented Jan. 3 1928.

uui'rso' STATES PATENT FEICEL ROBERT L, BLANDTEHG, Q33 ERQVIDEHGEE, EllQDE IhLMl'ED.

The present invention relates broadly to the art of heat exchangers, and more partic= ularly to tubular heaters, condensers, cool-. ers or the like of such improved construction as to effectively take care of the dimensional changes of the tubes, without the con sequent disadvantages of certain of the structures which have heretofore been pro=- vided for this purpose.

One type or heat exchanger constructed to take care of tube expansion as herein cpntemplated has embodied the so called rer: rule or ferrule packing. it has been found in actual practice that ferrules screwed into or otherwise secured in a tube' plate, while permitting the desired elongation oi the tubes, are generally unsuitable where either high pressures or high temperatures are to be dealt with. in practice, the ferrules usually fit into receptacles in the tube plate and surround the tubes. A soft packing is generally used under the ferrules prevent leakage, but obviously such packing is only effective for moderate pressures and temperatures. i lhere high temperature 1s encountered, it is dificult to provide a pas ing that will permanently maintain its so ing characteristics, although the construction is such as to efiectively permit tubes to be freely elongated due to expan= sion when heated. Where the pressure is high, there is likewise considerable dig: culty in preventing leakage from the liquid side to the steam side of the heat exchan er. It will thus be apparent that such cc struetion has a limited range of use be with respect to temperature and pressure,

So called floating heads have also Z ;i used with considerable success in an to solve this problem, but such constructions are not only expensive, but they are not immune from trouble where very high temper atures are encountered. Where but a single floating head is used, there is often a severe distortion thereof, due to the fact that tubes in difierent parts of the nest or nests are at different temperatures, and consequently,"

expand difierently, thus unevenly straining eith r the tubes or the other parts of thestructure. Floating head heat exchangers also have limitations with respect to the number of. passes for fluid circuiation. Where one head is fixed and the other floating, there is considerable diificulty in having anything but an even number of passes which in some cases prohibits the use of such a construction. Also, since the shells must either be made considerably large than the tube nest or else belied out at the floating head end to accommodate such head with hs flanged ends, there is necessarily an increase both in the cost and the size of the resulting apparatus.

In still other cases, so called hair pin tubes have been used. Such a construction efiectively takes care of tube expansion, but has the distinct disadvantage in that there is no convenient and efiective manner of cleaning the inside of the tubes in the event they become scaled up. They do not co1npare in this respect with straight tube installations, in which a rod or brush can easily be run therethrough in a manner not possible with the hair pin type tubes. Such I a heat exchanger also has one of the disadvantages inherent in the use o1 a floating head type construction in that an even number of passes is necessary.

' Recourse has also been had to coiled tube heaters, but such heaters have so many limitations, both with respectto operation and construction, that the use thereof is confined to a very limited. type of service. The

impossibility of efiectively cleaning the colled'tubes also rules them. out of many places where strai at tube heaters would be eminently satisfactory. v

It is one ofthe objects of the present invention to provide a type of heat exchanger which obviates the disadvanta es referred to, but in which the various ddvantageous features of construction and operation are retained. In theapparatus constructed in accordance with the present invention, both of the tube heads are fixed, whereby the expense 0t the'fioating head type is elimi-- nated to a considerable extent. I am also v.able to do away with the packed type of ice ' end of the shell, there may .be provided a 7 rigidly mounted tube plate or head 5, there without departing from the spirit of the invention or the scope of the broader claims;

In the drawin s: v

Figure l is a dongitudinal sectional view throu h a. heat exchanger'constructed in accor ance with the present invention; the tubes and heads, however, being shown in elevation;

Fi ure 2 is a transverse sectional view on the line II-II of Figure 1, looking in the direction of the arrows;

Figure 3 is a view similar to Figure. 1;

Figure 4 is a transverse sectional view on the line IV-I'V of Figure 3, looking in the direction of the arrows;

Figure 5 is a diagrammatic view illustrating the circumferential and angular-pro gression of the tubes. 3

In accordance with the present invention, there may be provided a shell 2 of any desired construction and material,'provided with an inlet 3 for the heating fluid and an outlet 4 for the condensate. Adjacent each being an inlet chamber 6 adjacent one of the tube plates and an outlet chamber 7 cooperating with the other tube plate, these chambers having an inlet 8 and an outlet 9, respectively.

Arranged within the shell and extending from one of the tube plates to the other is a plurality of tubes 10, these tubes, as indicated in Fi ure 2, preferably'being arranged in a plurality of concentric circles. In Figure 1, for the sake of clearness, only the outside circle of tubes is indicated. In-

. stead of constructing the heat exchanger in such a manner that the tubes extend in substantially a straight line, ffrom one end of the heat exchanger to the other, the tubes are preferably of such construction that they follow substantially the path of a helix, all of the tubes in any one circle following substantially similar helical paths. -This dis position of tubes necessarily involves a circumferential progression of the tubes in any of the tube circles, but this circumferential progression' is suchthat internal cleaning may be accomplished witlrcomparative case. In. other words, the departure of the tubes from true straightness is not so meat in any instance, but that a brush or-otlder cleaning means; may easily be passed through the tubes by means of an elastic rod, or such that the well known rubber cleaning slugs or the like may be easilyforced through the tubes by pneumatic or hydraulic pressure.

If desired, there may be provided a supporting means 11, conveniently in the form of a plate, cooperating with the tubes for i limitin deflection thereof or limiting vibration. uch a construction is particularly advantageous where com aratively long tubes are being used. hlS supporting means is preferably so located that the openinr therein which embraces an particular tu e will lie substantially mi way in the path of circumferential progression of such tube.- This is clearly shown in Figure 1 of the drawings, from which it will appear that the point where the tubes pass through the supporting plate is substantially midway between the juncturcs of the tubes with the tube plates, measured on the circumference of the circle in which such tubes lie. \Yhen the tubes expand, their natural deformation will be substantially as indicated by the dotted lines in Figure 1, it being apparent that, with the construction shown, there is no tendency toward the suppression of the deforming tendency caused by elongation of the tubes undertemperature. In other words, aconstruction as herein illustrated enables the building of a heat exchange apparatus in which the supporting means while limiting deflection and restraining vibration, does not in any manner restrain the natural expansion of the tube, this expansion being in a clockwise direction adjacent one end of the apparatus and in a counter-cloclnvise direction adjacent the opposite end thereof.

While Figures 1' and 2 of the drawings indicate a heat exchanger havin only a single pass, it will be understood t at any-desired number of passes .is possible.- It will likewise be understood that the tubes may be arranged otherwise than in concentric circles and that different. tubes may have. a circumferentiatpro rcssion either in the same or in opposite directions. In all cases,

tin

ion

however, T preferably mount the tubes ad- 4 jacent the inner portion of the heat ex tubes in the outer circles were right to give the desired flexibility thereof to permit deformation under expansion without undue strains on such tubes or onthe rest of the.

structure. This applies with equal force whether the tubes are arranged in concentric circles or are grouped in any other lesired manner.

In order to clearly set forth exactly what is meant by the expression circumferential progression and angular progression, it may be stated that if when facing one of the tube plates, one of the tubes be selected and its path followed to the next tube plate on the opposite end of the heat exchanger, it will be found that on the particular circle space existing between from which the tube is selected, the tube has traveled a certain distance-'in'its helical path. This travel is herein termed circumieren-- tial progression. The angular progression,

on the other hand, is the angular amountthat any tube progresses in its helical path from end to end of its length.

' In Figures 3 and l, there is illustrated a modified embodiment of the invention for the purpose of showing the adaptability thereof to a multiple-pass heat exchanger.

'3 and 4, the header 12 has an inlet 13 and an outlet 14, the header 15 at the opposite end of the heat exchanger being merely for the purpose of directin the fluid, as indicated by the arrows. Within the header 12 is a division wall 16 of such nature as to make a two-pass heater.- This division wall necessarily takes up a certain amount of space on the tubefplate 5 with which it cooperates, which space would, in a single-pass heater, 'be utilized for the installation of tubes, as indicated for example in Figures 1 and 2. This space and the corresponding the tubes is referred to herein as the void space, and is indicated by the reference letter S. If the division wall 16. is substantially horizontal,

'it will be apparent that a transverse sectional view through the tubes adjacent this tube plate, as indicated in Figure i, will show the void space as being substantially horizontal. all the tubes had the same I angular progression, the void space on the opposite end of the condenser would have substantially the position indicatedby the dotted lines S in Figure i, thus providing tube plates which are dissimilar with respect to symmetry about the transverse axis of a heat exchanger. On the other hand, if the tubes had a constant circumferential proression, the lines S would necessarily be curved or of irregular contour, inasmuch as a constant circumferential progression would necessarily require a greater angular progression of the tubes adjacent the center of the heat exchanger than of the tuhes adjacent the outside thereof.

In Figure 5 of the drawings, there is indicated diagrammatically the condition which would obtain if a constant circumferential progression, as just referred to, were employed. In this figure, there is indicated by solid circles the row of tubes 10, starting below the void space S on one of the tube plates. In dotted circles there is indicated the corresponding position of these tubes shown.

Certain advantages of the present invention arise from the provision ofa heat 'e'xchanger utilizin tubes which may be easily cleaned and in w ich ezpansional elongation is permitted, while' preventing leakage or other objectionable tendencies at either high temperatures or pressures.

Other advantages of the invention arise from the provision of a heat exchanger in which the tubes follow substantially a helical path froin end to end.

Still other advantages of the invention arise from the provision of a heat exchanger in which the tubes have a circumferentlal or angular progression from end to end, and

preferably, in which the angular progression of tubesedjacent the center of the heatexchanger is greater than the angular projection of tubes adiacent outside thereof.

Still further advantages arise from the provision of an apparatus which tubes of any desired length he utilized and supported against deflection and vibration at a desired point, without restraining thenatural tendency of thetubes to ezpansional elongatron.

I claim:

1. in a heat exchanger, a shell, and inner and outer tubes therein, said tubes havin an angular progression from end toend with certain of. said tubes havinga greater angular progression than other of said tubes, substantially as described.

2. in a heat e'rcnanger, a shell, and inner and outer tubes therein, said tubes having an angular progression from end to end with certain of said tubes having a greater angular progression than other of said tubes, the tubes having the greater angular progression being located adjacent the center of the heat exchanger, substantially as described.

3. In a heat exchanger, a shell, a plurality of tubes extending substantiall longitudinally of said shell and disposed in substantially concentric circles, each of said tubes havlng a circumferential progression in their respective circles from end to end thereof, substantially as described. I

4:. In a heat exchanger, a shell, a plurality of tubes extending substantially lonoitudh nally of said shell and disposed in substantially concentric circles, each of said tubes having an angular progression in. their respective circles from end to end thereof with the angular progression of the tubes in lit) the inner circles greater than the angular 11. In a heat exchanger, tube plates, tubes M progression of the tubes in the outer circles, substantially as described.

5. In a heat exchanger, a shell, a plurahty of tubes extending substantially longitudinally of said shell and disposed in substantially concentric circles, each of .said tubes having an angular progression in their respective circles from end to end thereof, the angular progression of the tubes gradually increasing from the outer to 'theinner cirales, substantially as described.

(3. In-a heat exchanger, a shell, tube plates therein, tubes carried by said plates, and

supporting means for said tubes located substantially midway between'said plates, said tubes being of such helical contour that when expanded in length by heat they show substantially no tendency to displace that portion of the tubes cooperating with said sup-,-

porting means, substantially as described.

7. In a heat exchanger, a shell, tube plates therein, tubes carried by said plates, and

supporting means for said tubes located substantially midway between said plates, saidthe tubes adjacent the center of the nest hav-'- ing a greater angular progression than the tubes more remote therefrom, substantially as described. I

9. In a heat exchanger, tube plates, tubes carried by said plates and so positioned as to provide void spaces thereon, the void spaces being located dissimilarly in relation to a plane including the longitudinal axis of the heat. exchanger, substantially as dc-' scribed.

10. In a heat exchanger, tube plates, and tubes carried by said plates, said tubes cooperating With said plates to provide void spaces so located that no similar void spaces on respective Plates are in line one with the other, substantially as described.

carried by said plates, said tubes cooperating with said plates to provide void spaces so located that no similar void spaces on respective plates are in line one with the other, and support ng meansintermediate said tube plates for said tubes, substantially as described. c

12. In a heat exchanger, tube plates, and tubes carried by said plates and providing a void space therebet-Ween, said void space having an angular progression throu hout the lcngthof the heater, substantialy as described.

13. In a heat exchanger, tube plates, and tubes carried by said plates and providing a void space therebetween, said void space having a circumferential progression throughout the length of the heater, substantially as described.

14. In a heat exchanger having spaced apart heads, tubes extending longitudinally of the heat exchanger, the tubesbeing helical and'having substantially the same curvature from head to head. e

15. In a heat exchanger having spaced apart heads, tubes extendin longitudinally of the heat exchanger, the tu es being helical and having substantially the same curvature and having substantially the same curvaturefrom head to head, and a tube support intermediate the heads, the intermediate support having openings thercthrough to 'accommodate the tubes.

17; In a heat exchanger having a head at each end, tubes extending from head to head,

the tubes being helical and having substantially the same curvature from head to head,

but making less than a full turn from head to head. v

18. In a heat exchanger having a pair of spaced apart heads; tubes extendin 'from head to head, the tubes being helica for at least a portion of their length, but making less than a full turn from head to head.

In testimony whereof I have hereunto set my hand.

ROBERT L. BLANDING. 

